U.S. patent number 5,738,733 [Application Number 08/657,786] was granted by the patent office on 1998-04-14 for ferrous metal glassy alloy.
This patent grant is currently assigned to Research Development Corporation of Japan. Invention is credited to Akihisa Inoue.
United States Patent |
5,738,733 |
Inoue |
April 14, 1998 |
Ferrous metal glassy alloy
Abstract
The present invention provides a ferrous metal glassy alloy
having temperature interval .DELTA.Tx of supercooled liquid as
expressed by the following formula: (where, Tx is an onset
temperature of crystallization, and Tg is a glass transition
temperature) of at least 40 K, which realizes magnetic properties
as a bulky alloy.
Inventors: |
Inoue; Akihisa (Sendai,
JP) |
Assignee: |
Research Development Corporation of
Japan (Kawaguchi, JP)
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Family
ID: |
15183630 |
Appl.
No.: |
08/657,786 |
Filed: |
May 31, 1996 |
Foreign Application Priority Data
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|
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Jun 29, 1995 [JP] |
|
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7-136792 |
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Current U.S.
Class: |
148/304;
148/403 |
Current CPC
Class: |
C22C
45/02 (20130101); H01F 1/15308 (20130101) |
Current International
Class: |
C22C
45/00 (20060101); C22C 45/02 (20060101); H01F
1/153 (20060101); H01F 1/12 (20060101); C22C
045/02 () |
Field of
Search: |
;148/403,304 |
Other References
"Fe-Based Ferromagnetic Glassy Alloys with Wide Supercooled Liquid
Region", Materials Transactions, JIM, vol. 36, No. 9 (1995), pp.
1180-1183. .
"Multicomponent Fe-Based Glassy Alloys with Wide Supercooled Liquid
Region before Crystallization", Material Transactions, JIM, vol.
36, No. 10 (1995), pp. 1282-1285. .
"Thermal and Magnetic Properties of Bulk fe-Based Glassy Alloys
Prepared by Copper Mold Casting", Materials Transactions, JIM, vol.
36, No. 12 (1995), pp. 1427-1433. .
"Effect of Additional Elements (M) on the Thermal Stability of
Supercooled Liquid in Fe.sub.72-x Al.sub.5 Ga.sub.2 P.sub.11
C.sub.6 B.sub.4 M.sub.x Glassy Alloys", Materials Transactions,
JIM, vol. 37, No. 1 (1996), pp. 32-38..
|
Primary Examiner: Yee; Deborah
Attorney, Agent or Firm: Wenderoth, Lind & Ponack
Claims
What is claimed is:
1. A ferrous metal glassy alloy, comprising at least one metal
selected from the group consisting of aluminum, gallium, indium and
tin, at least one semi-metal element selected from the group
consisting of phosphorus, carbon, boron, silicon, and germanium,
with the balance being iron, and
wherein the ferrous metal glassy alloy has a temperature interval
.DELTA.Tx of a supercooled liquid of at least 40 K, as determined
by the following formula:
where Tx is an onset temperature of crystallization and Tg is a
glass transition temperature.
2. The ferrous metal glassy alloy according to claim 1, comprising,
in atomic percentage:
from 1 to 10% aluminum,
from 0.5 to 4% gallium,
from 9 to 15% phosphorus,
from 5 to 7% carbon,
from 2 to 10% boron, and
the balance being iron,
wherein the alloy may contain incidental impurities.
3. The ferrous metal glassy alloy according to claim 2, further
comprising from 0.5 to 2% silicon.
4. The ferrous metal glassy alloy according to claim 2, further
comprising 0.5 to 4% germanium.
5. The ferrous metal glassy alloy according to claim 1, further
comprising up to 7%, in atomic percentage, of at least one element
selected from the group consisting of niobium, molybdenum, hafnium,
tantalum, tungsten and chromium.
6. The ferrous metal glassy alloy according to claim 1, further
comprising up to 10%, in atomic percentage, of nickel.
7. The ferrous metal glassy alloy according to claim 1, further
comprising up to 30%, in atomic percentage, of cobalt.
8. The ferrous metal glassy alloy according to claim 1, which is
annealed.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a ferrous metal glassy alloy. More
particularly, the present invention relates to a novel metal glassy
alloy, available as a bulky alloy having a far larger thickness
than a conventional amorphous alloy thin ribbon, excellent in
magnetic properties.
2. Description of Related Art
Some of the conventional multi-element alloys are known to have a
wide temperature region in which they are in a state of a
supercooled liquid before crystallization and constitute metal
glassy alloys. It is also known that these metal glassy alloys form
bulky alloys having a far larger thickness than the conventionally
known amorphous alloy thin ribbon.
The metal glassy alloys known as above include Ln-Al-TM, Mg-Ln-TM,
Zr-Al-TM, Hf-Al-TM, and Ti-Zr-Be-TM (where, Ln is a lanthaned metal
and TM indicates a transition metal).
However, none of these conventionally known metal glassy alloys are
magnetic at room temperature, and this has lead to a significant
restriction in industrial uses.
These alloys, while showing the supercooled liquid state, have no
practicability because of a small temperature interval .DELTA.Tx of
the supercooled liquid region, i.e., the difference (Tx-Tg) between
the onset temperature of crystallization (Tx) and the glass
transition temperature (Tg), practically resulting in a poor metal
glass-forming ability. To judge from this fact, the presence of an
alloy which has a wide temperature region of supercooled liquid and
is capable of forming a metal glass through cooling would overcome
the thickness restriction imposed on a conventional amorphous alloy
thin ribbon and should metallurgically attract the general
attention. In practice, however, the conventional metal glassy
alloys which are not magnetic at room temperature have been under
inevitable limitations.
SUMMARY OF THE INVENTION
The present invention was developed in view of the above-mentioned
circumstances, and has an object to provide a novel metal glassy
alloy which overcomes the limits in the conventional technology,
permits manufacture as a bulky metal, and further allows
application as a magnetic material.
The present invention provides a ferrous metal glassy alloy which
comprises a ferrous alloy having a temperature interval .DELTA.Tx
of a supercooled liquid as expressed by the following formula:
(where, Tx is an onset temperature of crystallization, and Tg is a
glass transition temperature) of at least 40 K.
The present invention provides also embodiments wherein the
above-mentioned alloy contains, together with iron, other metal and
semi-metal elements, wherein the other metal elements are at least
one selected from the group consisting of the metal elements of the
III-B group and the IV-B group, and wherein the semi-metal elements
are at least one selected from the group consisting of phosphorus,
carbon, boron, silicon and germanium.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a photograph of an electron diffraction pattern in
place of a drawing of Example 1;
FIG. 2 shows an X-ray diffraction pattern of Example 1;
FIG. 3 shows a DSC curve of Example 1;
FIG. 4 shows a B-H curve of Example 1;
FIG. 5 shows an X-ray diffraction of Example 2;
FIG. 6 shows a DSC curve of Example 2; and
FIG. 7 shows a B-H hysteresis curve of Example 2.
DETAILED DESCRIPTION OF THE INVENTION
As described above, the present invention provides a novel magnetic
metal glassy alloy at room temperature, which permits formation of
a bulky alloy so far unknown.
Among ferrous alloys, Fe-P-C, Fe-P-B and Fe-Ni-Si-B ones are
observed to exhibit glass transition. These alloys have however a
very small temperature interval .DELTA.Tx of up to 25 K of the
supercooled liquid, and cannot practically form metal glassy
alloys. The metal glassy alloy of the present invention has in
contrast a temperature interval .DELTA.Tx of the supercooled liquid
of at least 40 K or even at least 60 K, which represents a
remarkable temperature region which has not been anticipated at all
to date as a ferrous alloy from conventional findings. Furthermore,
the alloy of the present invention excellent also in magnetic
properties is actually novel and is far superior in practical
applicability to the conventional amorphous alloys applicable only
as thin ribbons.
The alloy of the present invention is characterized by a chemical
composition, as described above, mainly comprising iron and
containing other metal and semi-metal elements. Of these, the other
metal elements may be selected from the group consisting of metal
elements of the II-A group, the III-A and III-B groups, the IV-A
and IV-B groups, the V-A group, the VI-A group and the VII-A group,
or more appropriately, metal elements of the III-B group and the
IV-B group, including, for example, aluminum, gallium, indium and
tin.
Such metals as titanium, hafnium, copper, manganese, niobium,
molybdenum, chromium, nickel, cobalt, tantalum and tungsten may
also be blended.
Applicable semi-metal elements include, for example, phosphorus,
carbon, boron, silicon and germanium.
More specifically, the ferrous metal glassy alloy of the present
invention comprises, in the following amounts, in atomic
percentage:
______________________________________ aluminum from 1 to 10%,
gallium from 0.5 to 4%, phosphorus from 9 to 15%, carbon from 5 to
7%, boron from 2 to 10%, and iron balance
______________________________________
and may contain incidental impurities. Also it may contain from 0.5
to 2% silicon or 0.5 to 4% germanium.
Another embodiment covers an alloy composition containing, in
addition to any of niobium, molybdenum, chromium, hafnium, tantalum
and tungsten in an amount of up to 7%, up to 10% nickel and up to
30% cobalt.
In any of the embodiments of the present invention, the ferrous
metal glassy alloy has a temperature interval .DELTA.Tx of a
supercooled liquid of at least 40 K, or even at least 60 K.
In the present invention as described above, the metal glassy alloy
can be manufactured through melting and casting, or quenching by
means of a single roll or dual rolls, or further the
in-rotating-liquid spinning process or the solution extraction
process, or the high-pressure gas atomization, into bulk, ribbon,
wire or powder shape. In this manufacture, there is available an
alloy having a thickness and a diameter more than ten times as
large as those for the conventional amorphous alloy.
These alloys show magnetism at room temperature and a better
magnetism as a result of an annealing treatment. They are therefore
useful for various applications as a material having excellent soft
ferromagnetic properties.
As to manufacture, it should be added that an optimum cooling rate,
depending upon the chemical composition of the alloy, means for
manufacture, and size and shape of the product, may usually be set
within a range of from 1 to 10.sup.2 K/s as a standard. In
practice, the cooling rate may be determined by confirming whether
or not such crystal phases as Fe.sub.3 B, Fe.sub.2 B, or Fe.sub.3 P
precipitates in the glassy phase.
Now, the metal glassy alloy of the present invention is described
further in detail by means of working examples.
EXAMPLE 1
Iron, aluminum and gallium metals, an Fe-C alloy, an Fe-P alloy and
boron as raw materials were induction-melted in an argon
atmosphere, and cast into an alloy ingot of Fe.sub.72 Al.sub.5
Ga.sub.2 P.sub.11 C.sub.6 B.sub.4 in atomic ratio. A ribbon having
a cross-sectional area of 0.02.times.1.5 mm.sup.2 was prepared in
an argon atmosphere from the thus prepared ingot by the single
roller melt-spinning process. It was confirmed through an X-ray
diffraction and a TEM that the resultant ribbon had a metal glassy
nature. Glass transition and crystallization were evaluated by
means of a differential scanning calorimeter (DSC).
FIGS. 1 and 2 illustrate an electron diffraction pattern and an
X-ray diffraction pattern, both demonstrating that the above alloy
is of the glassy phase. FIG. 3 illustrates a DSC curve, suggesting
that the alloy has a temperature interval of supercooled liquid,
which represents the temperature difference (Tx-Tg) between the
glass transition (Tg) temperature and the onset temperature of
crystallization (Tx) of 61 K.
As a result of measurement at a scanning rate of 0.33 K/s by means
of a differential thermal analyzer (DTA), the above alloy has a
melting point (Tm) of 1,271 K, giving a ratio Tg/Tm of 0.58.
Evaluation of magnetic properties of the alloy revealed that the
as-quenched alloy and the alloy after an annealing treatment at 723
K for 600 s exhibited hysteresis B-H curves with 1.59 kA/m at room
temperature as shown in FIG. 4, respectively. Bs, He,
.lambda..sub.s and .mu.e were as shown in Table 1.
TABLE 1 ______________________________________ As-quenched Annealed
______________________________________ Bs (T) 1.07 1.07 Hc (A/m)
12.7 5.1 .lambda.s 2.0 .times. 10.sup.-6 -- .mu.c 3600 9000 at 1
kHz ______________________________________
This result suggests that the above-mentioned metal glassy alloy
has excellent soft ferromagnetic properties.
EXAMPLE 2
An alloy having an atomic composition of Fe.sub.73 Al.sub.5
Ga.sub.2 P.sub.11 C.sub.5 B.sub.4 was melted in the same manner as
in Example 1, and a bar-shaped alloy sample having a circular
cross-section was prepared through injection molding in a copper
die. The sample had a length of about 50 mm and a diameter of from
0.5 to 2.0 mm. Forming was carried out under a pressure of 0.05
MPa.
Observation of the outer surface permitted confirmation that the
alloy has a smooth surface and a satisfactory metallic gloss, with
a good formability. Then, after etching the alloy with a solution
comprising 0.5% hydrofluoric acid and 99.5% distilled water at 293
K for 10 s, the cross-section was observed by means of an optical
microscope. This microscope observation revealed that a crystal
phase was non-existent and the alloy comprised a glassy phase.
The results of an X-ray diffraction analysis for samples having a
diameter of 0.5 mm and 1.0 mm are shown in FIG. 5: broad peaks are
observed only at and around a 2.theta. of 43.6.degree. and a peak
corresponding to a crystal phase is not found at all. This suggests
the fact that, even with a diameter of 1.0 mm, the resultant alloy
comprises a glassy phase.
FIG. 6 illustrates DSC curves for alloy samples having diameters of
0.5 mm and 1.0 mm and a ribbon sample as in Example 1. In all
cases, the curves demonstrate a glass transition temperature (Tg)
of 732 K, an onset temperature of crystallization (Tx) of 785 K and
a temperature interval of supercooled liquid (.DELTA.Tx) of 53
K.
FIG. 7 shows a hysteresis B-H curve. Magnetic properties were
confirmed to be equivalent with those in Example 1.
It is needless to mention that the present invention is not limited
at all by the above-mentioned examples, and that various
embodiments are possible as to its chemical composition,
manufacturing process, annealing treatment, shape and the like.
According to the present invention, as described above in detail,
there is provided a ferrous metal glassy alloy which overcomes the
restrictions such as the thickness of conventional amorphous alloy
thin ribbon, can be supplied as a bulky alloy, and is expected to
be applicable as a material having magnetic properties.
* * * * *